[CMake] Enable ARM target in Fuchsia toolchain

[phosek]

Summary

This is still used by some users of Fuchsia toolchain. Also include llc and opt which is useful for development and testing.

[mcgrathr]

lgtm

cfe/trunk/cmake/caches/Fuchsia-stage2.cmake

 # This file sets up a CMakeCache for the second stage of a Fuchsia toolchain
 # build.
 
-set(LLVM_TARGETS_TO_BUILD X86;AArch64 CACHE STRING "")
+set(LLVM_TARGETS_TO_BUILD X86;ARM;AArch64 CACHE STRING "")
 
 set(PACKAGE_VENDOR Fuchsia CACHE STRING "")
 
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_TOOL_CLANG_TOOLS_EXTRA_BUILD OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB ON CACHE BOOL "")
 set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")

 set(BUILTINS_x86_64-fuchsia-none_CMAKE_SYSROOT ${FUCHSIA_SYSROOT} CACHE STRING "")
 set(BUILTINS_x86_64-fuchsia-none_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
 set(BUILTINS_aarch64-fuchsia-none_CMAKE_SYSROOT ${FUCHSIA_SYSROOT} CACHE STRING "")
 set(BUILTINS_aarch64-fuchsia-none_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")
 
 # Setup toolchain.
 set(LLVM_INSTALL_TOOLCHAIN_ONLY ON CACHE BOOL "")
 set(LLVM_TOOLCHAIN_TOOLS
+  llc
   llvm-ar
   llvm-cov
   llvm-cxxfilt
   llvm-dwarfdump
   llvm-dsymutil
   llvm-lib
   llvm-nm
   llvm-objdump
   llvm-profdata
   llvm-ranlib
   llvm-readobj
   llvm-size
   llvm-symbolizer
+  opt
   CACHE STRING "")
 
 set(LLVM_DISTRIBUTION_COMPONENTS
   clang
   lld
   lldb
   liblldb
   LTO
   clang-format
   clang-headers
   builtins-x86_64-fuchsia-none
   builtins-aarch64-fuchsia-none
   runtimes
   ${LLVM_TOOLCHAIN_TOOLS}
   CACHE STRING "")